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Method for Achieving Task Independence in a Multiple Virtual Terminal Environment

IP.com Disclosure Number: IPCOM000061778D
Original Publication Date: 1986-Sep-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Baker, DC: AUTHOR [+3]

Abstract

A method is described to establish multiple interactive task independence in a single interactive task environment. The standard UNIX* environment is a single interactive task per physical terminal. With the introduction of virtual terminals, many interactive tasks may run on a physical terminal. Though each of these tasks is logically independent, the UNIX task model does not distinguish between them and, hence, they are physically dependent and interact with one another. In accordance with the new method, each logically independent task is created with a separate process group ID and each virtual terminal is associated as the controlling terminal for that process group. This ensures independence among concurrently executing interactive tasks.

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Method for Achieving Task Independence in a Multiple Virtual Terminal Environment

A method is described to establish multiple interactive task independence in a single interactive task environment. The standard UNIX* environment is a single interactive task per physical terminal. With the introduction of virtual terminals, many interactive tasks may run on a physical terminal. Though each of these tasks is logically independent, the UNIX task model does not distinguish between them and, hence, they are physically dependent and interact with one another. In accordance with the new method, each logically independent task is created with a separate process group ID and each virtual terminal is associated as the controlling terminal for that process group. This ensures independence among concurrently executing interactive tasks. The new method also operates to anchor multiple interactive tasks to ensure logical ending of a user log-in session. In the multiple execution thread extension of the UNIX environment, the INIT process as an anchor for user log_in session may cause a "logger" to be created on a user's initial virtual terminal despite the fact that the user may have other tasks running concurrently in virtual terminals that were created as part of the initial log-in session. Hence, the user can hot-key between a log-in screen and his other tasks. In accordance with the new method, an activity manager is provided as the anchor for user log-in sessions. This ens...